Armstrong Anatomy Guide
This will be a helpful guide where you’ll learn more about the different components of your new DIY robot arm - Armstrong.
We'll start with bigger components and cover smaller components later in the guide.1. Circuit boards
The black boards you've gotten in your kit are called circuit boards.
Professionals call them printed circuit boards or PCBs.
A PCB is a laminated sandwich structure of conductive and insulating layers.
What does it do?
Your circuit board has two functions:
- It holds all the electronic components in place.
- It provides electrical connections between the electronic components.
Because of the circuit board, all electronic components can work together as a team.
What are those tiny lines on my circuit board?
They allow electrical charges to flow between components. This way, electronic components are powered, and they can do clever stuff using electricity.
What is my circuit board made of?
Circuit boards are usually made out of fiberglass-reinforced epoxy-laminated sheets.
These are also referred to as “FR4” sheets.
The FR4 sheets are used as the insulating non-conductive material, and copper is used as a conductive material.
If a material is conductive, it conducts electricity; electrical charge can flow through that material easily.
FR4 and copper are both sandwiched together in thin sheets, and that’s how you get a circuit board.
Where are PCBs used?
They’re used everywhere!
In your phone, in your laptop, in your refrigerator, air conditioner. Basically, every electronic device you use has a unique printed circuit board that makes it work.
Did you know?
A PCB is one of the most important inventions of the last 100 years.
Space travel wouldn’t be possible without them.
PCBs were invented by Paul Eisler.
He invented it in the 1930s, but the predecessors of modern-day PCBs have been around since the age of gramophones and vacuum tube radios, just in a somewhat different form.
2. ESP-32
That part is called a microcontroller, and it runs everything. If the PCB was a body, this part would be the brain.
One of the key features of the ESP-32 is its integrated WiFi and Bluetooth capabilities, which make it an ideal platform for building IoT devices.
3. Pushbuttons
The pushbuttons can be pressed to activate specific commands on your device.
When you push on them, they complete the circuit and allow electricity to flow through, which can trigger an action.
You can find this 6mm THT pushbutton on Armstorngs’ Brain board:
4. FPC/FFC Connector
A Flexible Printed Circuit (FPC) connector, also known as a Flexible Flat Cable (FFC) connector, is an electrical connector used to connect flexible printed circuitry (FPC) or flat flexible cables (FFC) to other electronic components or circuit boards.
These connectors are designed for applications where space is limited or where flexibility and low-profile connections are required.
5. Servo motors
Servo motors are a type of rotary actuator widely used in various applications, including robotics, automation, and control systems.
They work based on a closed-loop control system, aiming to maintain a precise position or angle of the motor's output shaft.
They operate by receiving a control signal, comparing the desired position with the actual position using feedback, and making continuous adjustments to the motor's operation to achieve and maintain precise control over its position or angle.
This makes them ideal for applications requiring accurate and controlled motion.
The ones used on Armstrong are called MG90S, and this is what they look like:
6. Encoders
Encoders are devices used in various applications to convert mechanical motion into electrical signals or digital data.
They provide information about the position, speed, or direction of a rotating shaft or object. There are two primary types of encoders:
1. Rotary Encoders: These are used to measure the angular position of a rotating shaft. They generate electrical signals or digital pulses in response to shaft rotation, allowing precise tracking of position changes.
2. Linear Encoders: These are designed to measure linear motion along a straight path. They are commonly used in machinery and equipment to provide accurate feedback on the position of components such as machine tool slides or conveyor belts.
Encoders play a crucial role in various industries, including manufacturing, robotics, automation, and control systems, where precise and real-time feedback on position or motion is essential for accurate operation and control.
This is what the Rotary Encoders on Armstrong look like:
7. LEDs
These electronic components will light up on your Armstrong.
LED stands for light-emitting diodes.
LEDs convert electrical energy into visible light.
This is an electronic symbol for a light-emitting diode:
Watch out - LEDs are polarized!
This means that they only allow current to flow in one direction.
Because of this, you need to pay attention to how you are going to place your LED in the electronic circuit.
The tiny metal legs of every LED are not the same length.
They mark polarity!
The positive leg is longer (we call this one the anode), and the shorter leg is negative (we call this one the cathode).
If you put the LED in the wrong way, it won't light up because the electrical energy will not be able to flow through it.
Electrical energy flows from the anode to the cathode, not in the opposite direction.
Resistors and LEDs make a great team!
LEDs can be damaged if they receive too much energy.
Resistors will limit the amount of electrical energy flowing through the circuit and save your LEDs from getting damaged.
Historical fun facts:
A Russian inventor Oleg Vladimirovich Losev made the first LED in 1927.
Did you know?
LED lightbulbs are the most efficient type of lightbulbs.
Unlike “regular” “old” bulbs (we call these incandescent lightbulbs), which release 90% of their energy as heat, LEDs use energy far more efficiently with very little wasted heat.
There are also some smaller components on Armstrong, like:
1. Resistors
Resistors are the most basic electronic components found in almost every electronic device.
They fall in the category of passive electronic components.
Passive electronic components do not generate electrical power and do not need electrical power to work.
They just modify the flow of electrical energy in their own unique way. 
Resistance
Resistors have a property of resistance - they lower the amount of electrical energy flowing through the circuit.
You could say that they “resist” the flow of electrical energy.
The unit of resistance is called Ohm and it was named after a German physicist, Georg Simon Ohm.
Resistors are used for tasks such as adjusting the flow of electricity through an electronic circuit.
The exact value of a resistor is measured with a device called an ohmmeter.
Can we compare it to something we see in everyday life?
If we make an analogy to water flowing through pipes, the resistor is a thin pipe that reduces the water flow.
Scientists and engineers have come up with different symbols for each and every electronic component.
This is an electronic symbol for a resistor:
2. Capacitors
A capacitor is a component that has the ability to store energy, much like a small rechargeable battery.
It can absorb energy from a circuit and store it temporarily.
Later on, this stored energy can be released back into the electronic circuit.
Capacitance
We can measure the ability of a capacitor to store electrical energy.
We call this property - capacitance.
The unit of capacitance is called Farad (we use the letter F as short for Farads).
This unit was named after an English physicist, Michael Faraday.
Historical fun facts:
Capacitors were discovered by Pieter van Musschenbroek a looong time ago - in 1746.
The first capacitor was a glass jar wrapped inside and out by a thin metal foil.
This is an electronic symbol for a capacitor:
3. Color sensor
Color sensors are electronic devices designed to detect and measure the color of objects or surfaces.
These sensors work by analyzing the wavelengths of light reflected or emitted by the object and providing information about its color.
Color sensors are commonly used in various applications, including industrial automation, color detection in manufacturing, etc.
This is what the one on Armstrong looks like: